Several types of apparatus are in use which are capable of variable printing at a relatively high rate of speed using computer formated information. Principal among these are ink jet and electrostatic laser printers. For example, printing processes which apply liquid droplets of ink from jets to a web are shown in U.S. Pat. Nos. 3,560,641 and 3,577,198. However, as known at this time, only black inks are applied by ink jet processes and apparatus. Such inks are limited to solutions of dye at low concentration in water. Thus, such inks must be free from particles and are thus not capable of carrying magnetic materials or other pigments which are needed for machine reading of the printed material. Furthermore, such inks, being limited to black color, are not capable of printing other desired colors.
Methods are known for fixing images consisting of dry powder on paper, such as shown in U.S. Pat. No. 3,640,749. However, such methods require the use of an aqueous dispersion of a film forming synthetic resin.
It is an object of this invention to provide an apparatus and a method for applying a coating to wet images to provide colors which are not necessarily black.
Another object of this invention is to provide an apparatus and a method in which particles are applied to the wet image and fused so that the printed material can be read by magnetic scanning or optical scanning means, or the like.
Another object of this invention is to provide such an apparatus and method by which raised printing can be produced at a high rate.
Another object of this invention is to provide printed images and/or coatings with high gloss, unique texture, fluorescence, and other aesthetic and functional features.
It is another object of this invention to provide such apparatus and method which does not require the use of synthetic resins.
Still another object of this invention is to provide an apparatus and method for manufacture of quality "hidden image" games and the like.
It is another object of this invention to provide apparatus and a method by which a waterproof, or an abrasion resistant or a non-erasable coating is applied to a printed web.
Another object of this invention is to provide such an apparatus and method by which, instead of conventional ink, a colorless liquid is applied in a desired configuration to a web and to which powdered material is then adhered to the wet image surface to provide color or magnetic qualities or the like to the configuration.
Another object of this invention is to provide an apparatus and method for producing a carbonless image transfer coating to the surface of a substrate.
Other objects and advantages of this invention reside in the construction and arrangement of parts and in the methods and modes of operation involved, as will become more apparent from the following description.